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Lobe pumps are similar to external gear
pumps in operation in that fluid flows
around the interior of the casing. Unlike
external gear pumps, however, the lobes do
not make contact. Lobe contact is prevented
by external timing gears located in the
gearbox. Pump shaft support bearings are
located in the gearbox.

Lobe Pump Overview
Lobe pumps are used in a variety of
industries including, pulp and paper,
chemical, food, beverage, pharmaceutical,
and biotechnology. They are popular in these
diverse industries because they offer superb
sanitary qualities, high efficiency,
reliability, corrosion resistance, and good
clean-in-place and service-in-place
(CIP/SIP) characteristics.
Rotary pumps can handle solids (e.g.,
cherries and olives), slurries, pastes, and
a variety of liquids. If wetted, they offer
self-priming performance. A gentle pumping
action minimizes product degradation. They
also offer continuous and intermittent
reversible flows and can operate dry for
brief periods of time. Flow is relatively
independent of changes in process pressure,
too, so output is constant and continuous.
Rotary pumps also offer superior CIP/SIP
performance. Once in line, they can be
cleaned without being removed. Depending on
the application, it is a good idea to check
with the manufacturer to make sure if a
particular lobe pump meets both 3-A
requirements.
As a general rule, rotary pumps require very
little maintenance. Some manufacturers offer
pumps that allow for seal servicing and
maintenance with the pump in line.
How
Lobe Pumps Work
Lobe pumps are similar to external gear
pumps in operation in that fluid flows
around the interior of the casing. Unlike
external gear pumps, however, the lobes do
not make contact. Lobe contact is prevented
by external timing gears located in the
gearbox. Pump shaft support bearings are
located in the gearbox, and since the
bearings are out of the pumped liquid,
pressure is limited by bearing location and
shaft deflection.
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As the lobes come out of mesh, they
create expanding volume on the inlet
side of the pump. Liquid flows into the
cavity and is trapped by the lobes as
they rotate.
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Liquid travels around the interior of
the casing in the pockets between the
lobes and the casing -- it does not pass
between the lobes.
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Finally, the meshing of the lobes forces
liquid through the outlet port under
pressure.
Lobe pumps are frequently used in food
applications because they handle solids
without damaging the product. Particle size
pumped can be much larger in lobe pumps than
in other PD types. Since the lobes do not
make contact, and clearances are not as
close as in other PD pumps, this design
handles low viscosity liquids with
diminished performance. Loading
characteristics are not as good as other
designs, and suction ability is low.
High-viscosity liquids require reduced
speeds to achieve satisfactory performance.
Reductions of 25% of rated speed and lower
are common with high-viscosity liquids.
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Advantages
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Pass medium solids.
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No metal-to-metal contact.
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Superior CIP/SIP
capabilities.
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Positive suction,
nonpulsating discharge.
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Disadvantages
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Applications
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Food and cosmetic products
capable of being pumped by lobe
rotor pumps.
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Alcohol
Apple purée
Apricots
Baby food
Batter
Beans
Beer
Beetroot
Biscuit Cream
Blackcurrants
Brine
Broth
Butter fat
Caramel
Castor Oil
Cat food
Cheese curd
Cheese whey
Cherries
Chicken paste
Chili con carne
Chocolate
Chutney
Cockles
Coconut oil
Cod oil |
Coffee liquor
Cordials
Corn oil
Corn syrup
Cottage cheese
Cotton seed oil
Cranberry juice
Cream
Cream cheese
Custard
Dog food
Dough
Eggs - whole
Egg yolk
Essences
Evaporated milk
Fish
Flavorings
Fondants
Fruit juice
Fruit pulp
Fruit - whole
Fruit yogurt
Gelatin
Gherkins
Glucose |
Glycerin
Gooseberries
Gravy
Hand cream
Honey
Horseradish
Ice cream
Icings
Iodine ointment
Jams
Jelly
Ketchup
Lard
Liquid sugar
Lotions
Malt
Maple syrup
Margarine
Marmalade
Marshmallow
Marzipan
Mascara
Mayonnaise
Milk
Mincemeat
Molasses |
Mousse
Mussels
Mustard
Nail polish
Nail varnish
Offal
Olive oil
Onions
Palm oil
Pastes
Peanut butter
Pectin
Perfumes
Piccalilli
Pie fillings
Pizza toppings
Plasma
Potato salad
Preserves
Purées
Quinine
Rice pudding
Salad dressing
Shrimps
Soap
Solvents |
Sorbitol syrup
Soup
Soya sauce
Spirits
Starches
Stews
Strawberries
Sugar
Syrup
Tapioca
Tea
Tomato ketchup
Tomato paste
Tomato purée
Toothpaste
Vaseline
Vegetables
Vinegar
Water
Wines
Wort
Yeast
Yogurt |
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